1. Field of the Invention
The present invention relates to an insole, and more particularly to a multiply insole having a better resilience and air permeability than that of the prior art insole.
2. Description of the Background
The conventional insole is defective in that the resilience thereof would die out after wear. An improved insole intended to provide a solution to the problem described above was disclosed in a U.S. patent bearing U.S. Pat. No. 4,642,912. The insole is characterized in that it has three layers being made of the same flexible foam material but different in compressive strength thereof. As a result, the insole has good retention of its cushioning properties after wear. But according the fact, the three-layer insole of the invention only provided 15 percent better cushioning than the prior art insole. In other words, the drawback of the prior art can not resolve effectively. In addition, the air permeability of the three-layer insole reduced due to the fact that it is laminated by so many layers made of same foam material.